1. Field of the Invention
The present invention generally relates to image reproduction machines, such as printers and copiers, and more particularly relates to apparatus for receiving and stacking printed paper sheets discharged from such machines.
2. Description of Related Art
Inkjet printers have recently become quite popular adjuncts to personal computers due to their simplicity, reliability, relatively low cost and relatively high print quality. Despite this popularity, however, two well known limitations are commonly associated with inkjet printers of conventional construction.
First, as each printed sheet exits the printer its ink is still wet and the printing must be isolated against contact with other sheets (or other portions of the printer) until the ink is dry to avoid smearing of the sheet. Typically, each successively printed sheet drops, printed side up, onto the top of a stack of previously printed sheets. Since the page/minute printing rate of most inkjet printers currently available is relatively low (on the order of about two to five pages per minute) the ink on each sheet usually has sufficient time to dry before the next sheet comes into contact with the ink. However, inkjet printers are currently being developed with substantially greater printing rate capacities (on the order of 20 pages per minute). When these printers become available the potential for one discharged sheet from contacting and smearing the ink on the previously printed sheet will be greatly increased.
Second, in conventional inkjet printers the printed sheets discharged from the printer are stacked with the first printed sheet on the bottom of the stack and the last printed sheet on the top of the stack. This requires, for each print job, that the printer operator remove the printed stack and laboriously reverse the sheet order therein to provide the proper text sequence in the stack. Additionally, when looking at the discharged stack the operator cannot usually tell at a glance which of several print jobs he is looking at since the visible top sheet is the last sheet in the print job as opposed to its title sheet which is on the bottom of the stack. This reverse stacking order problem is not limited to inkjet printers but also exists in the realms of laser printers as well as other types of image reproduction machines such as copiers. While this problem may be overcome by programming the machine to print the pages in reverse order (so that they will be stacked with the first sheet on the top and the last sheet on the bottom), this undesirably increases the memory requirements of the machine.
It can readily be seen from the foregoing that it would be desirable to provide improved image reproduction and paper handling apparatus, such as an inkjet printer, that eliminates or at least substantially reduces the above-mentioned problems, limitations and disadvantages commonly associated with conventional image reproduction machines of the type generally described above. It is accordingly an object of the present invention to provide such improved apparatus.